1. Field of the Invention
The present invention relates to a battery pack control apparatus and battery pack control method for controlling a battery pack including a plurality of unit cells that are electrically connected in series.
2. Description of Related Art
In a related starting system for an internal combustion engine, a battery pack includes a plurality of unit cells that are electrically connected in series. If one or more unit cells becomes overdischarged in the course of supplying power (i.e., during normal discharge of power) to an electric starting motor for the engine, then the remaining capacity of the battery pack may be reduced to such an extent as to make it difficult to start the engine. As it is used herein, the term “overdischarged” refers to supplying power beyond the proper unit cell voltage, i.e., at or below a minimum voltage for the unit cell. Overdischarging may occur due to insufficient capacity of a battery pack that causes the battery pack to be overworked, and may reduce the cycle life of the battery pack.
In a related battery pack control apparatus, separate voltage detectors for each unit cell sense a reduction in voltage equal to or less than a predetermined voltage in an individual unit cell. When a load is applied to the related battery pack control apparatus, power that is supplied by a battery pack may be restricted when the voltage of any unit cell is detected by its corresponding detector to be equal to or less than the predetermined voltage. Thus, the related battery pack control apparatus suffers from a number of disadvantages as a result of providing separate detectors for each unit cell, including increases in the size and cost of the related battery pack control apparatus.